Domestic type stoker



s sheets-sheetl 1 F. KAY

DOMESTIC TYPE sToKER'v Filedr Nov. s, L1928 June 13;y 1933.

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F. w. KAY

-noMEsTIc TYPE sToKER Filed Nov. 5, 1928. 6 Sheets-Sheet 3 June 13,1933.` F. w. KAY 1,913,396

DOMESTIC TYPEsToKIgR Filed Nav. s, 1928 v s sheets-sheet 4 June 13,1933. Wr KY DOMESTIC TYPE sToKER e sheets-sheet 5 Filed Nov. s, 1928June 13, 1933.` F. w. KAY 19,913,396

DOMESTIC TYPE` STOKER Filed. Nov. 3, 1928 6 Sheets-Shes?I 6 4 vsoPatented June 13, 1933 mural)y STATES PATENT QFFICE rFRANK W. KAY, FPHILADELPHIA, PENNSYLVANIA', ASSIGNOR i T0 AMERICAN ENGINEERING COMPANY,0F PHILADELPHIA, PENNSYLVANIA, A CORPORATION 0F PENNSYLVANIA Applicationled vNovember My invention relates to stokers, and it has for one objectthe provision of a relatively small stoker particularly applicable for dmestic use, such, for example, as apartment houses and the like. Anotherobject of my invention is to provide a Stoker unit of the characterdescribed which may be readi-'lyinstalled in existing.`

furnaces with a minimum alteration.

Still another object of my invention is to provide a stoker comprisingmeans whereby the fuelmay be automatically fed through the usual firingdoor and the ashes subsequently automatically discharged through theusual ashdoor.

A further object of my invention is to provide a removable stoker unitadapted for household use, small industrial plants, theatres, oilicebuildings' and the like, comprising means for feeding lfuel into thefurnace, means for moving theY fuel through the furnace, means forcrushing the resulting' ashes and common driving apparatus for saidmeans. l z5 A still further object of my invention is to provide afuel-feeding plunger with a detachable head portion positioned in spacedrelation thereto, the head portion. being.

v formed to exert a feeding as well asa spreading action on thefuel.

A still further object of my invention is to provide in combination witha fuel-feeding passage, means whereby the fuel may be spread over adesired portion of the width of the stoker.

Otherpbjects-fand applications of my invention, as well 'as details'ofconstruction and operation, whereby Vmy'invention may be practiced, willbe apparent more fully hereinafter, when taken in connection with theaccompanying drawings, wlierein l Fig. 1 is a vertical, longitudinalsectional view through a domestic type furnace embodying my invention;

Figs. 2, 3 and L11a-re vertical sectional views taken on the lines 2 2,3 3, and 4-4, respor-tively, vof Fig. 1; i' f Figs. 5 and 6 are detail,top plan and rear elevational views, respectively, of the fuelspreadingmeans; v

DOMESTIC TYPE STOKER 3, 1928. Serial N'o. 317,065.

Figs. 7 and 8 are similar views of the extension means for use inconnection with the structure of Figs. 5 and 6;

Figs. 9 and 1() are transverse, sectional views taken on the lines 9--9and 10-10 of Fi s. 5 and 7, respectively;

`igs. 11 and 12'are top plan views of the stationary center and side`grate plates, respectively;

Fig. 13 is a side detail, side elevational view of the driving mechanismshown in Fig. 1;

Fig. 14 is an end elevational view of the structure of Fig. '13; and yFigs. 15 and 16 are sectional views taken on the lines 15--15 and 16-16,respectively, of Fig. .13.

' Referring to Fig. 1, the structure therein Shown comprises a domestictype furnace 1 having a front wall 2 provided with an upper opening 3enclosed by a firing door 4.- and also a lower opening 5 enclosed by anash door 6. A stoker unit 7 for the furnace 1 comprises broadly a fuelpassage 8 which extends through the firing door 4 and opening 3; a gratestructure 9 which extends rearwardly from the fuel passage 8 andterminates in spaced relation to a rear wall 11 of the furnace to forman ash pocket 12; an ash crusher 13; a drag or conveyor 14 positioned4in a passage 15 for removing the ashes in the pocket 12 from the furnace1 through the ash door 6 and the opening 5 in the Afurnace front wall 2;and common driving apparatus 16 for the `stoker positioned just in frontof the furnace wall 2.

whorizontallyfpositioned valve 26. The dis- ConsideringV the stoker unitembodied in charge ofthe fuel through the vertical Side 23 rather thanthrough one of the inclined sides 22. as well as the offsetting of thepassage 25 tends to prevent the arching of the fuel in the bottom of thehopper and the consequent closingof the opening 24.

The valve controlled passage 25 is connected to an upper end 27 of apassage 28 which is formed in a ram casing 29. The passage 28 opens intoa horizontal passage 31 in the casing 29 intermediate front and Arearends 32 and 33. Fuel in the passage 31 may be Inoved rearwardly by meansof a ram plunger 34 which extends through the open end 32 of the casing29. The portion of the casing 29 forming the passage 31 is ofrectangular` cross section and is provided with a removable bottomwall35, permitting replacement in the event of damage thereto. The portionof the passage 31 between the rear end 33 thereof and the passage 28 isslightly flared vertically, 'affording the plunger 34 a loose fit whenpositioned therein. Experience has shown that such construction tends toprevent the pulverizing of the fuel and the subsequent blocking of thepassage 31.

The movement of the fuel, as Well as the subsequent spreading thereof,is facilitated by the mounting of a ram or plunger head portion 36 inspaced relation to the main body portion plunger 34 on a rod 37extending therebetween, asshown in Fig. 1. The plunger head portion 36is of block-like form and is provided withI a` lower Side 38 .whichslidably engages the bottom wall 35 of the passage 31; .verticalsidefaces 39 and 41 which are positioned in spaced relation to" verticalside walls 42 and 43 of the ram casing 29, Fig. 5; and front and rearfaces`44 and 45; The front face 44 is so beveled that when the ramextension or head portion 36 is moved forwardly, the fuel in passage 29moves readily over the same with a minimum retarding force. The rearface 45 is so formed that when the head portion 36 is actuated in arearward direction, a scooplike effect is exerted on the fuel, causingnot only a forward bodily movement thereof, but also an upward movementof that portion of the fuel which is directly in engagement with thebottom wall 35 ofthe passage 31. As a result of this upward movement ofthe fuel, a force is exerted on the head portion 36 tending to maintainthe same in sliding engagement with the bottom Wall 35. Therear face 45is also so formed as to exert notonly lilfting but also a spreadingeffect on the To this end, l provide the face 45 with la pair of beveledside surfaces 46 and 47,

46 and 47 cause a desired spreading of the fuel. Each of the surfaces46,47 is provided with an upper vertically-extending portion 49 and alower curved portion 51. The portions 49 afford the principalfuelabutting surface, causing a rearward movement of the fuel, while theportions 51, in combination with the portions 49, tend to exert thedesired scoop-like effect on the fuel. Thus, the fuel is not only movedrearwardly during the working stroke of the ram 34 and head portion 36,but also upwardly from the bottoln wall 35, as well as laterally intoengagement with' the adjacent portions of the side walls 42 and 43. i

The ram casing 29 is mounted in the firing door4 and extends into thewall passage 3. In order to cause the further spreading of the fuel, aspreader casing 52 is mounted on the rear end 33 of the ram casing 29,thereby forming an end portionA for the fuel passage 31. The spreadercasing 52 comprises rearwardly diverging side walls 53 and 54, a bottomwall 55 and a removable top wall 56. r1`he bottom and top walls 55 and56 are slightly flared, as shown in Fig. 1, sothat theV end portion ofthe passage 31 may also increase in depth. The spreading of the fuel isincreased by providing the bottom wall 55 with rear corner portions 57and 58 which are flared to a greater extent than a 'central p0rtion 59.i 1

lThe fuel leaving the flared end of the passage 31 moves onto a spreaderextension 61, comprising a bottom wall 62 and side walls v63 and 64.Inner sides 65 and 66 of the Walls 63 and 64 are contiguous to thecorresponding sides of the walls 53 and 54, respectively,

thereby forming .continuous diverging walll surfaces. A front flange 66extends forward.- ly from the spreaderextension 61 and it 1s offset,` asshown in Fig. 1, so as to provide a supporting shoulder for the rearedge .portion of the spreader casing 52. The flange 66 is supported on across beam 68, the ends of which are mounted in side walls 69 and 71 ofthe stoker unit. lA relative movement between the spreader extension 61and the spreader casing 52 is prevented by a pair of centering lugs 72and 73 which fit complementary recesses 74 and 75 formed in a front edgeportion 76 of the extension 61. The offset flange y67 may be extendedparallel to the angled sidewalls and 66. Rear end portions 77 and 78 ofthe side walls 65 and 66 are respectively mounted on the Stoker sideWalls 69 and 71 as shown Lin F ig. 7. Y

The bottom wall 62 of the spreader exten: sion 61 is .provided with acentral, rearwardly inclined portion 79 constituting a continuation ofthe inclined central portion 59 of the spreader casing 52, and alsoinclined side portions 80 and 81 constituting continuations of thespreader casing portions 57 and 58, re-

spectively. The side walls 63 and 64 are preferably hollow, providingair chambers 82 which extend slightly above the upper level of the'fuelbed. Apertures 83 and 84, near the upper sides of the chambers 82,permit the escape of air so as to prevent the formation of dead airpockets. The spreading effect of the plunger head portion 36, thespreader casing 52 and the spreader extension 61 may be Aincreased bymeans of a spreader melnber 85, Figs. 1, 2 and 5. The member 85 isprovided with a pair of beveled side faces 86 and 87 terminating in avertical -front edge 88 which is substantially in front to rearalignment with the rear edge 48 of the ram extension 36. The member 85is also formed with a beveled rear face 89 which extends from atransverse rear edge portion 91 forwardly and upwardly,'as shown inFig. 1. As a re'- sult of the several spreading means, just described,the fuel as it finally passes over a rear edge portion 92 of thespreader extension 61 Figs. 1, 2 and 3 of the drawings. Each of the Ifour central or intermediate series of grate plates comprises alternatestationary and movable plates 96 and 97, respectively. The stationaryplates 96 of-each intermediate series are mounted in spaced relation onhol'izontal step-like portions 98 of spaced longitudinally extendingsupporting beams 99, the front ends of which are secured to flangeportions 101 of a supporting front beam 68, while rear end portions aresecured to the cross beam 93. The longitudinal beams 99 are mounted at102, intermediate their ends, on a main cross beam 103 which extendsbetween the-Stoker side walls 69 and 71.

Considering further the detail structure of the stationary grateelements 96. of which Fig. 11 is a top plan View and which are shown insection Figs. 1, 2, 3 and 4, each is provided with a rear or exposedportion 106 th-e hollow or recessed under side 107 of which constitutesa grate air chamber. The upper face of the rear portion 106 comprises apair of horizontal port-ions 108 and 109 e in stepped relation, and aplurality of air openings 111 are provided in the intervening wall 112,affording air outlets for the grate chamber. Similar air openings 113are formed in the lower rear edge of the plate portion 109. The rearportion 106 may be supported on flanges 114 form-ing the horizontalstepelike portions 98 of the beans 99. illustrated in Figs. 2, 3 and 4.

The rear exposed portion 106 of each of the stationary grates isextended forwardly by means of spaced side edge portions 115 yand 116Which are also mounted on the 65 flanges 114, as-shown'in Fig. 4. Eachof these extensions comprises a horizontal sup. porting portion 117which directly engages the flanges 114 and is provided with recesses 118for clamping bolts 119. The bolts. 119 extend through the flanges 114,the recesses 118 and a plate 121. The plate 121 is so mounted as toextend over the opposite recess 118 of the projecting portion 116 of thenext stationary grate plate. Each of the extensions 115, 116 is alsoprovided with a vertical wall 122 having a shoulder 123 over-` hangingthe horizontal portion 115 and ex. tending longitudinally thereof. Asupporting lug 124 extends upwardly from the horizontal portion 115, sothat abearing surface 125 is positioned in spaced relation to a beveledunderside 126 of the overhanging portion 123.

As shown in Fig. 4,"each of the movable grate plates 97 is provided withdepending side walls 127 and 128, front portions of which are slidablymounted on the supporting lugs 124, 124 of the spaced, stationary-4grate project-ions 115 and 116. Inner edges 129 of each of these wallsare projected inwardly and beveled complementary to the adjacentoverhanging lbeveled portions 123, thereby interlocking therewith so asto pres vent an upward vertical movement of the movable grate platewhile permitting a rela. tive longitudinal movement thereof. Inthismanner, the rear end of each of the movable grate plates is slidablyinterlocked with the extensions 115 and 116 of the next lower stationarygrat-e plate. The rear end vof each 100 of the'intermediate movablegrate plates is slidably mounted on the horizontal wall portion 108 ofthe next lower grate plate in the series.

The two longitudinal side 01 terminal se- 105 vries of grate plates alsocomprise alternate stationary and movable plates. Fig. 12 is a top planView of one of the stationary plates, wherein it is noted that forwardextensions 131 and 132, which correspond to the exten- 110 sions andl116 of the stationary grate plate previously described, .are providedwith raised supporting lugs 133 for slidably supportingthe side flanges127 and 128 of the next higher movable. grate plate. Lugs 134 115 alsoextend outwardly from the spaced projections 131 and 132 into recesses135 and 136 formed respectively in an inner wall portion 137 of thestoker side wall, and into a recess 138 formed in the horizontal portion'120 115 of the next adjacent stationary grate plate. A second pair oflugs 139 may also be extended from the side walls of this stationarygrate plate -into similar recesses formed in the Stoker side wall and inthe rear portion 106 of the adjacent stationary grate plate. V ertiealmovement of the movable grate plate is prevented by means'of i beveledside projections 141 and 142. The projection 141 fits under a. shoulder143 130 5. grate plate.

formed just above the recess 135 in the stoker side wall. The portion142 lits a complementary groove 144 in a lower corner of the side wall127 of the next adjacent stationary Thus, each 'of the stationary grateplates is interlocked with the stoker side wall and a stationary grateplate of the adjacent intermediate series, while each of the movablegrate plates is slidably mounted on the next lower stationary grateplate and interlocked with the stoker side wall and the movable grateplate of the adjacent intermediate series.

The passage of siftings Ibetween the upper, front row of movable grateplates and the rear edge portion 92 of the spreader extension 61 isprevented by means of a bar 145 which is loosely mounted in a recess 146formed in a lower side 147 of the edge portion 92. As shown in Fig. 1the bar 145 slidably engages the upper sides of the movable grate platesforming the upper row, thereby preventing not only the passage ofsiftings but also constituting a wind seal preventing air from enteringthe adjacent portion of the fuel bed and the consequent burning of theedge portion 92 of the spreader extension 61.

Each of the `upper movable grate plates is connected with the next lowermovable grate plate in its series by means of a pair of links 148, Fig.1, pivotally mounted thereon. A pin 149 extends between these links andfits in a recess 151 formed in an end portion 152 of a lever 153extending upwardly between the links 148. As shown in Fig. 2, each of-the levers 153 is mounted on a cross shaft 154 which may comprisesections 155 and 156. These sections are journaled in bearings 157carried by the stoker side walls, as well as the intermediate sidebeams. Adjacent ends of the sections 155 and 156 are connected by crankarmsv 158 to a longitudinally-extending link 159 passing outwardly ofthe Stoker through a bearing 161 positioned at the front end thereof.

A rear end of the link 159 is pivotally connected to a second link 162carried by a rod 163 j ournaled in a bearing 164. The bearing 164constitutes one part of a cross plate 165 which forms in a connectionwith the cross beam 93, the end wall 94. The rear end, of the rod 163 isconnected by a link 166 to a pivotally-mounted ash crusher 167 whichextends across substantially the full width of the stoker. The motionthus imparted to the upper pair of connected grate plates in each\`-,series may be imparted to the next movable grate 4plate by means, ofan adjustable lostmotion connection 168, and' from the lastmentionedgrate plate to the lower, rear movable grate plate by means of anadjustable lost-motion connection 169. In this way, the alternatemovable grate plates of each series maybe reciprocated and the movementthere- 173 and 174 and a bottom wall portion 175y which is directlymounted on the longitudinally-extending lower wall section 172. The

latter section may be directly mounted on a floor surface 176. The uppersection 170 is formed similar to the intermediate section 171,comprising side wall portions 177 and 178 and a top wall portion 179.Upper edges 181 of the side wall portions 173 and 174 are inclinedupwardly and forwardly while corresponding lower edges 182 of the upperwall portions 177 and 178 are oppositely formed so as to fit thereon.The edges 181, 182 thus formed extend upwardly and forwardly from theash pocket 12 just above the level of the grate surface of the structure9. The upper side 179 of the top section 170 extends along a line justabove the upper level of the fuel bed, terminating at a top side 183 ofthe side Wall portion 81 of the spreader extension 61. Each of the upperside Wall sections 170 is preferably provided with a plurality oflongitudinally-spaced depending tongues 184 which extend under similarlyspaced locking lugs carried by the intermediate section 171. These partsare so positioned that the interlocking relation is obtained by firstmounting the upper section 170 on the intermediate section 171 and thenmoving'the former section downwardly. A reverse movement of the upperwall sections 170 is normally prevented by the rear ends of the spreaderextension side walls 63 and 64 which are positioned in abutting relationto the front ends of the upper sections 170.

The inner side wall portion 17 4 of each of the intermediate side Wallsections is provided with an air opening 185 which is positioned below'the grate structure 9. Air may thus pass into the chamber formed by-the upper end intermediate sections 170 and 171, so that an air-back isformed. Inasmuch as it is desirable to have a continuous iow of airthrough these sections, a series of apertures 186 may be formed in theupper portion of the side Wall 178 of the upper section 170. The air maybe supplied to the air-backs inthe stoker side Walls, las well as to theunderside of the grate structure 9, through an air passage 187 leadingfrom a fan 188 through the ash door 6. The air passage 187 may comprisean outer` section 189 and an inner section 190.- The outer section isconnected to the fan 188 while the inner section extends through the ashdoor 6 and opens into the -air chamber formed directly beneath the gratestructure 9. An outer end of the section 190 serves to support thebearing plate 161.

A bottom wall 191 of the air chamber formed under the grate structure 9comprises a plurality of cross plates 192 the ends of which areconnected by filler plates 193 to the lower side Wall sections 172. Theplates o 192 are mounted in spaced relation 'to the floor level 176 soas to form the ash-discharge passage 15. The Wall thus formed extendsfrom the rear end Wall 94 to a removable bottom wall 194 of the airpassage 187. -Air is thus prevented from blowing into the ashdischargepassage and is confined to the region immediately below the vgratestructure 9. The ash discharge passage 15 is provided -eral movableparts of the stoker unit 1.

with the ash conveyor 14, the innerv end of which extends into the ashvpocket 12, While the outer end passes through 'the ash door 5 and isconnected by a passage 195 to an eXteriorly-positioned ashreceivingrecepwhile Figs. 13 to 16, inclusive, illustrate the tioned pin 217. Thepin 217 is connected by same in ,different sectional views. As thereinshown, a main driving motor 196 is connected by Worm-and-Wheel mechanism197 to a driving pinion 198 meshing with a gear-wheel 199 mounted on avertically-extending shaft 201. The upper end of the shaft 20L carries abevelgear-Wheel 202 which engagesa bevel gear-Wheel 203 mounted on ahorizontally- `positioned shaft 204. The bevel gear-wheel 203 -mesheswith a bevel gear-Wheel 205 mounted on a shaft 206, an upper end ofwhich carries a crank disk 207. The crank disk 207 has an adjustablymounted bear lng 208'for an outer end of a connecting rod 209,permitting variations in the stroke thereof. An inner end of theconnecting rod 209 is securedto the ram 34.

One end of the shaft l204 is secured to a crank disk 211 which carriesan adjustably mounted pin 212. The pin 212 is connected bylever 213 andlinkage to the ash conveyor 14 and serves to actuate the samelongitudinally in the passage 15. Another end of the shaft 204 isconnected by a clutch 214 and gear-Wheel mechanism 215 to a third crankdisk 216 which carries an adjustably-posilinkage 218 to thelongitudinally-movable driving link 159, so that motion may be impartedto the movable grate plates 97 of the grate structure 9. The' drivingmotor 196 also operates the fan 188, causing a supply ofair underpressure to the underside of the grate structure 9.

In operation, assuming the clutch 214 in its closed position, theenergization ofthe driving motor 196 causes the rotation of severalcrank disks, as Well as the operation of the fan 188. The movement ofthe crank disk 207 causes the reciprocation of the ram, 34 with its headportion 36, resulting in the feeding of fuel from the hopper 17 throughthe fuel passage 31. The head extension 36, in combination withthespreader casing 52, the spreader extension 61 and the spreader block 85,results in the even distribution of fuel over the full width of theStoker as it passes onto the upper movable grate plates.

The turning of the crank disk 216 results inthe reciprocation of themovable grates in each of the longitudinal series, so that the fuel isslowly passed through the furnace.

The fuel is prevented from engaging the sidel walls of the furnace byreason of the stoker side Walls 69 and 71, which extend above the upperlevel of the fuel bed. As the ashes discharge from the grate structure9, the crusher 13 which is also actuated from the crankA disk 216,causes the crushing of the clinkers. The operation of the fan 1.88 alsocauses a supply of air to the underside of the grate structure 9,thereby, establishing desired combustion conditions inthe fuel bed. Theturning of the crank disk 211 through its lever 213 and linkage resultsin the relciprocation ofthe ash conveyor 14, so that as the ashes dropto the bottom of the pocket 12, they are conveyed through the passage l5and finally discharged into the recess 195.

Hence, the foregoing stoker structure constitutes a self-contained unitWhich may be readily inserted in existing furnaces with a minimum ofalteration. The unit automatically functions to cause the feeding offuel onto the grate structure 9 through the usual firing door 4 from thehopper 17; the move.-

,ment of the fuel through the furnace; the

supply of air to the fuel bed, so as to support combustion; the crushingof the clinkers formed during the combustion of the fuel; and theremoval of the ashes through the `usual ash door. By reason of thecompactness of the unit, the minimum number of parts, and the ease ofcontrol, it. readily lends itself to domestic use, such as apartmenthouses, or to small industrial plants, such as'are found in theatres,office buildings and the like.

While I have shown only one form of embodiment of my invention, for thepurpose of describing the same and illustrating its principles ofconstruction and operation, it is apparent that various changes andmodifications may bemade therein, Without departing from the spi-rit ofmy invention. I'

for domestic use, of a Stoker unit comprising a plurality of stationaryand movable grates adapted to support a fuel bed, reciprocatory meansfor feeding fuel onto said grates, reciprocatory means for removing theashes from said furnace, common driving apparatus for said means andsaid movable grates, and means controlled by said common drivingapparatus for supplying air under pressure to said grates.

2. Apparatus of the character described comprising, in combination,stoker side walls formed to constitute an air-back, means providing agrate surface extending between said side walls, a fuel-feeding passage,means positioned between said passage and said grate surface, wherebysaid fuel may be spread in a desired lnanner, said means having sidewalls also formed to constitute airbacks and positioned contiguous tosaid firstmentioned air-backs, said first-mentioned stoker wallscomprising upper, intermediate and lower sections, said upper andintermediate sections being provided with interlocking lugs detachableupon a relative longitudinal movement, the side walls of saidsecond-mentioned means being positioned to prevent said relativemovement.,

3. The combination with a furnace having a firing opening at the frontthereof, of means for feeding fuel into the furnace through said firingopening, and a grate structure positioned in said furnace ,to receivethe fuel, said grate structure inclining downwardly from said openingand comprising a longitudinal series of interspersed pushers andstationary plates arranged in relatively stepped relation, each of saidpushers comprising a forward elevated portion and a rearward relativelydepressed portion and having openings intermediate said portions and atthe rear end of said lower portion for admission of combustion air tothe fuel-bed, means for actuating said pushers to progressively advancethe fuel from the top towards the bottom of said grate structure, an ashpit at'the lower end of saidgrate structure, a passage leading from saidash pit to the front of the furnace, means for conveying ashes from thepit through said passage, and a partition extending from the lower endof said grate and underethe latter to the front of said furnace, saidpartition constituting the upper wall of said ash passage.

4. The combination with "a furnace having a firing opening, of means forfeeding fuel into the furnace through said opening, and a gratestructure positioned in said furnace to receive the fuel, said structureinclining downwardly from said opening and comprising a longitudinalseries of interspersed pushers and stationary plates arranged in steppedformation, each of said pushers andy stationary plates comprisinganelevated forward portion and a relatively depressed rear portion, andeach having openings intermediate said forward and rear portions and atthe rear ends of said lower portions for admission of combustion airtothe fuel-bed, means for actuating said pushers to advance the fuelprogressively over the said structure, aircooled side walls bounding theside edges of said grate structure, an ash pit at the lower end of saidstructure, and mechanism for discharging ashes from said pit to thefront of said furnace.

5. The combination with a furnace having a firing opening, of mechanismfor feeding fuel into the furnace through said opening, a gratestructure positioned in the furnace to receive the fuel, said gratestructure comprising a longitudinal series of pusher elementsinterspersed with stationary plates, longitudinal beams supporting saidstationary plates, means for securing said stationary plates to thesupporting beams, and means for slidably interlocking the pushers withlsaid stationary plates, means for actuating said pushers to advance thefuel longitudinally over said grate structure, air-cooled walls boundingthe sides of said grate structure and extending above the surfacethereof, an ash pit at the lower end of said structure, crushing meansoperative in said pit, and Va partition extending from the lower end ofsaid structure to the front of the furnace,

said partition forming the. upper wall of a 'passage extending from saidpit, and means for discharging ashes from said pit through said passage.

6. The `combination with a furnace having a firin opening, 0f means forfeeding fuel to the urnace through said opening, a grate Structurepositioned in said furnace to receive the fuel, said structure incliningdown wardly from said opening and comprising a longitudinal series ofpushers arranged in relatively stepped relation, means forinterconnecting the pushers of said series, a pivoted lever operativelyconnected with said interconnecting means, an operating rod connectedwith said lever, mechanism for recip-v rocating said rod to effect a.relprocatlon of said pushers, a partition extending from the lower endof said grate structure to the front of the furnace and forming achamber beneath the grate embracing said rod and lever, an ash pit atthe lower end of said grate structure, and a passage extending from saidpit and under said partition to the front of the furnace andconstituting a discharge outlet for said pit.

7 The combination with a furnace havingv a front wall provided withupper and lower openings, of means for feeding fuel ,into the furnacethrough lsaid upper opening, a gratei` structure positioned in saidfurnace to re-' ceive the fuel, said structure comprising a l pluralityof movable elements for advancing the fuel longitudinally over thestructure, an

ash-crushing element at the terminal end of said structure, an actuatingrod extending into the furnace through said lower opening, and meansconnecting said rod with said 5. movable grate elements 'and saidcrushing 'element respectively, andv mechanismv for actuating said rod.

8. In a Stoker, the combination with va grate structure including aplurality of re- ,10 ciprocating elements for advancing fuelprogressively over said structure, means for feeding fuel to the grateincluding a reciprocatory-ram, an ash pit, and reci rocatory meansassociated with said pit or re- A moving ashes therefrom, a pair ofhorizontal shafts each having a crank, said cranks being connectedrespectively with the ash-removing vmeans andthe reciprocatory grateelei ments, gearing connecting said shafts, a bevel 'gear carried by oneof said shafts, a vertical shaft having a bevel pinion meshing with saidgear, a horizontal crank on said vertical shaft operatively connectedwith the said ram, a motor, and means for operatively connecting saidmotor with the said bevel gear.

FRANK W. KAY.

